Date and Time
Bath Royal Literary and Scientific Institution, 16-18 Queen Square, Bath BA1 2HN
Plate tectonics is a grand paradigm in Earth Sciences that ties together many disparate observations. In order to conserve the Earth’s surface area, the creation and movement of oceanic plates is necessarily accompanied by their return (subduction) into the underlying mantle (that comprises 80% of the Earth by volume). The initial passage of the plate into the mantle can be observed seismically, but thereafter the fate of plates remains enigmatic. Do they sink and pile up at the bottom of the mantle or simply get mixed back up in convective flow? In order to attempt to resolve this question geochemists have used an increasingly wide range of natural tracers to see if any hint of ‘recycled’ oceanic crust is ever resampled at the surface. This talk will review some of the techniques behind this endeavour and report on its mixed success.
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